Fine wire drawing furnace



Oct. 13, 1959 l w. sT. JOHN ErAL 2,908,490

FINE WIRE DRAWING FURNACE Filed Nov. 23, 1954 2 Sheets-Sheet 1 INVENTORSWal. 57T ,qTa/ewf- 7T A. Hama/wv. BY

Oct. 13, 1959 Filed Nov. 23, 1954 W. ST.

FINE WIRE JOHN ETAL DRAWING FURNACE 2 Sheets-Sheet 2 FINE WIRE DRAWINGFURNACE William St. John, Bloomfield, and Thomas A. Hoffmann, t Newark,NJ., assignors to Westinghouse Electric Corf .Y poration, EastPittsburgh, Pa., a corporation of Pennsylvania Application November 23,1954, Serial No. 470,636

3 Claims. (Cl. 263-3) The present invention relates to the manufactureof be easily removed from its operating position while still hot tothread a wire over the pulley at the entrance to the furnace tunnel andthrough the wire drawing die, a furnace elevating mechanism is providedthat shifts the furnace backward and upward on two sets of pivotswithout jarring and thus damaging the furnace refrac-v tory. t v, Thewire drawing furnace of the present invention uni-Y formly heats thewire. Minor gas pressure liuctuations do` not effect wire temperature.Drafts are eliminated.

' 'Ihe wire is protected until it enters the die. Water incandescent anduorescent lamps and, more particularl ly, to a ltungsten or molybdenumwire drawing machine. The present tungsten or molybdenum wire drawingmachines reduce the size and weight of wire by passing the wire over apulley, through a furnace to heat it, and then 'through a preheated diehaving a smaller diameter hole therein. The furnace employed may consistof a -ilat manifold having approximately 200 burner tips formed in saidmanifold and from which the gas is emitted Vand burned. The manifold islocated underneath the wire and from time to time the burner tips becomeclogged with aquadag, the wire drawing 1ubricant, falling thereon. Inaddition, another of the defects of the prior art furnace is non-uniformheating of the wire as the wire passes over the individual burner tipsand in and out of the soft flame envelope thereof. y Minor gasfluctuations and drafts aect the flame locations and tend to producenon-uniform heating of the wire from the time it enters the furnaceuntil it leaves the die.

`Inthe past various types of U-shaped lgrids have been installed in thefurnace around the wire to indirectly heat the wire. Water jackets oneither side of the furnace` manifold have also been applied to protector bae themanifold from drafts and to conduct heat away from the workingparts of the Wire drawing machine.

Thesewater jackets require considerable maintenance due to leaks. Inaddition when water ow ceases, due to clogging of thevjacket, highpressure steam may develop within the jacket during operation'of thefurnace.

If the wire undergoing drawing is not uniformly heated, excessive wearon `the die itself reduces the die life and produces varying wire weightor diameter from one end of a piece ofv wire to the other. Obviouslypoorer machine efficiency and low production results from wire breakage,respooling and die replacement.

jackets and grids are not necessary. The burner does not clog. Inaddition, die life a's increased, wire breakage and attendant respoolingIis reduced and lgas savings are effected. Quality in the form of auniform weight of wire is improved and production in the form of totallength of wire drawn is increased. In its general aspect the presentinvention has as its objective elimination of the defects of the priorart design of Wire drawing furnaces.

A specific object of the present invention is a wire: drawing furnaceand in which the wire is completely' enclosed, indirectly heatedthereby, and enveloped in va; protective atmosphere until the wireenters the die.

AnA additional object is a wire drawing furnace whichi I is easilyremoved from its operating position without;

jarring and damaging the burner refractory.

' Other objects of the present invention will become apparent to thoseskilled in the art to which it appertains; as the description thereofproceeds. Referring now to the drawings in which like numerals: ofreference indicate similar parts through the severall views: Fig. 1 is aside elevational view of a wire drawing: machine incorporating the wiredrawing furnace of the: invention and showing the nonoperatingvor wireloading; position of the wire drawing furnace in dotted lines.

Fig. 2 is a vertical end view of the drawing die heath and the exit endof the Wire drawing furnace along the: line Il-II of Fig. 1 in thedirection of the arrows and.' showing the wire drawing furnace in itsoperating posii tion.

of Fig. l in the direction of the arrows, and showing the inoperativeposition of the furnace in dotted lines.

Other methods of heating the wire, such as surrounding t the wire with atube and heating the tube from the side by burners was foundunsatisfactory. Again, direct use of high frequency coils around thewire was found impractical and uneconomical.

Hence, it has been found advantageous according to the present inventionto'provide a wire drawing furnace for a` wire Vdrawing ymachinerwhichwill eliminate the above mentioned defects, increase production andimprove quality of the drawn wire while at the same time reducing thecost of production.

The furnace consists I of a tunnel-like body open at the bottom and atthe ends through which the wire passes. The tunnel walls are gas heatedfrom a ribbon extending along the length thereof so that the flamestherefrom' sweep down the furnace walls but do not impinge directly onthe wire undergoing drawing. The furnace of the present inventionpermits the wire to be completely enclosed, indirectly heated, andcontained within a protective atmosphere created by the products ofcombustion, which escape at the furnace ends, until the wire reaches tothe die.

"' In'order that the furnace of the present invention may Y bolts, tothe platform 14.

Fig. 4 is a vertical longitudinal sectional view of the wire drawingfurnace along the line IV-lV of Fig. 2 in the direction of the arrows.

Fig. 5 is an enlarged fragmentary vertical sectional view vof one of thepivot points of afurnace elevating mechanism along the line V-V of Fig.2 in the direction of the arrows and showing the operating lever thereofin its raised position.

VReferring now to the drawings, particulraly to Fig. l the referencenumeral 10 designates a wire drawing ma.- chine, particularly adaptedfor the drawing of ne tungsten or molybdenum wire 12-and which ismounted, as hereinafter described in detail, on a table or platform 14;

The wire `drawing machine 10 has a reel 18 mounted on a suitable shaftprojecting laterally from a bracket 20 upstanding from the table 14.This reel 18 carries the wire 12 which is to be drawn to a reducedweight and diameter by the machine l0. Adjacent to the reel 18 thevwirevpasses through -a lubricant cup 22 mounted on -a suitable holder V24upstanding from the table or platform and into a wire drawing furnace 30of the present invention. The wire drawing furnace 30 is mounted bymeans of a furnace elevating mechanism 31 on a bracket 32. The bracket32, in turn, is secured as by `Near the exit end of the furnace 30 theWire 12 passes through a drawing die head standing roller mountingbracket 48 may guide the nowv reduced drawn wire 12 from the `drawingdie head 40 to a` reel or speoling head 5,0 where the drawn Wire 1swound thereon in the usual manner. This -reel 50. is carried on ahorizontal shaft 52 projecting from an up-Y standingbearing 54 and isreciprocably traversed on s-aid shaft 52 by a reel traversing mechanism(not shown). In addition to the reel 50 the shaft 52 carries a drivenpulley S6, rotatable by suitable means, such as a belt 58 driven by amotor (not shown).

The elevating mechanism bracket 32 carries a channellike heat baffle 60`(Fig. 2), of generally shallow U-shaped vertical section, which extendssubstantially the length of the wire drawing furnace 30. and isjuxtaposed therebeneath when said furnace 30 is in its normally down oroperating position, shown in Figs. l and 2. The baffle 60.has lugs 61(Fig. 2) on one of its longitudinal sidewalls for limiting the downwardpivotal motion of the wire drawing furnace 30 from the uppernon-operating position (shown in dotted lines in Fig. l) to the loweroperating position.

Furnace lifting mechanism A pair of upstandi-ng pivot posts 62 of thewire drawing furnace elevating mechanism (Figs. 1, 2 and 5) projectupwardly from the bracket 32. Each post 62 is provided with ashaftsupporting hub portion 63 which has a generally horizontal uppersurface 66, as viewed in Fig. 5. A headed shaft or pin 64 extendsthrough and is rotatable in the hub portionV 63 of each of the pivotposts 62. The shafts 64, as viewed from left to right in Fig. l, carryoperating or furnace lifting levers 67 and 63 respectively. The lever-68has a hub encircling mounting flange 69, as shown in Fig. 5, and isprovided with a shoulder 70 of generally tapered contour. This shoulder70 becomes engageablewith upper surface 66 of the hub portion 63 tolimit the upward pivotable movement of the operating levers 67 and 68and hence the wire drawing furnace 30 to the dotted line position shownin Fig. 1= which position is beyond the dead center position, ashereinafter explained.

Each of the operating levers 67y and 68 has an upper shaft hub whichcarries a headed shaft or pin 72 (Figs. 1 and 2) projecting throughsuitable arcuate slots in a stationary side baille 74. The baffle 74 isaffixed to the heat baille 60, as bybolts which extend into a gasmanifold 90-of the wire drawing furnace 30. It will be understood thatthe lever 68 is` of the bell crank type and carries (Figs. 1- andl 2) anoperating handle 78 ('Fig. 2) projecting laterally therefrom,

It will be understood from a consideration of Fig. 1 that the levers 67and 68 (pivoted on the upper ends of the pivot posts 62) and a body 80of the wire drawing furnace 30 (pivotable on the shafts 72 carried onthe upper hubs of thelevers 67 and 68) form a pivotable parallelogramand constitute the wire drawing furnace lifting mechanism 31. By meansof the handle 78, the wire drawing furnace 30 can be swungcounterclockwise (Fig. 1) from its operating position within the baffle60 to its non-operating or wire loading position shown in the dottedlines of Fig. 1.

Wire drawing furnace 30 The metallic casting or body 80 (Figs. 3 and 4)comprises essentially an open topped box provided with wire entrance andexit clearance slots 82 in the end portions thereof and a longitudinalwire clearance slot 84 in the bottom face thereof which connects the endslots 82.

As shown in Figs. 3 and 4 particularly, a gas manifold 90 is secured bythe flanged portions thereof and suitable bolts 92i (Fig. 3) to the body80. Algas flow baille 96 is juxtaposed below a gas inlet connection 98of the manifold 90 to circulate the gas to all parts of the manifold 90.The bottom mounting flange of the gas manifold carries adjustable stops97 (Figs. 2 and 4) which engage lugs 61 on the baille 60 to limitdownward motion of the furnace 30. This flange of the manifold 90 issuitably machined to provide a shoulder 99 (Fig. 3) for the positioningtherein of a plurality of longitudinally stacked generally T-shapedburner tips 100 of suitable refractory material, such as a high gradefire clay, for example Kaolin, a trademark for a clay containing suchhigh alumina minerals as kynite or anda lusite. A suitable retainingplate gasket 102 fits about the Shanks of the burner tips 100 betweenthe flanged portions of the gas manifold 90 and a refractory retainingplate 104. secured to the flanged portion of the gas manifold 90, as bysuitable bolts, not shown.

Each of the burner tips 100 shown in Fig. 4 has an inverted Y-shaped gasslot or port (Fig. 3) cut in one face thereof. It will be understoodthat the gas burner groove 110 in a given burner tip 10|)y rests.against the flat face of the next burner tipl 100 thus providing a gasport for the passage of the gas therethrough. lThe upper end of each gasport 110, as viewed in Fig. 3, leads into the gas manifold 90. Thebottom aperture in each gas port 110 diverges the gas against acorrugated arcuate surface 112 of refractory reflectors 114, sui-tablyof the same refractory material as the burner tips 100.

As shown in Fig. 4 the arcuate corrugated refractory reflectors 114 oneither side of thevwire 12 comprise a series of sections fitted togetherin overlapping engagement. The corrugations 112 tend tol slow the flowof gas from the gas outlet portions of the gas ports 110. It will beunderstood that when the washboard surface of lthe reflector on eitherside of the wire 12 mayhave been heated, for example, to a white heat inthe neigh borhood of 1500-2000o C. the gas tends to burn not only at theopen gas port 110, but in an encircling arc which covers the entirecorrugated surface of the reflectors. This V.provides uniform heat tothe wire 12 passin through the wire drawing furnace 30. v

Between the longitudinal side walls of the casting or body 80 of thefurnace 30 and the refractory reflectors 114, suitable insulating orpacking material (Fig. 3) of a refractory nature, such as a hightemperature bonding cement or refractory mortar containingkaolinyprecalcined at a temperature over 3000 F., is providedfto insulate therefractory reflectors 114 from the sidewalls of the casting 80.

Die holder head The die holder head 40 (Figs. 1 and 2) has a generallyhollow flanged die holder castingl secured', as by bolts, through theflanged portions thereof (Fi'g. 1) to the mounting projection 42 of thebracket 32. Insulating plates or spacers may be juxtaposed between theVprojection 42 `and the casting 130. A die heater 1'32 (Fig. 11)'vsuitably a burner having a curved upper end, is secured to the table14', as by bolts, and projects upwardly through the generally hollowtriangular vertical cross section of the casting 130. The flame of theburner 132 isdirected against a die holder block or a block-like portion 134 of the casting 130.

' AS shown particularly in Fig. 2 the block 134, a portion of thecasting 130, is siutably slotted on either side of the die holderretaining portion thereof to provide adequate insulation and protectionto la heated die from drafts. The wire drawing die 140, maintaineddesirably at a temperature between 30G-400 C., is secured in the dieholder retaining portions of the block 134; The right hand end of theblock 134 when viewed in Fig. l, is suitably formed or machined toprovide a generally frustoconical guide and clearance hole for the drawnwire 12 as it leaves the die 140 and enters the guide rollers 44 and 46.

Thus, it will be seen from the foregoing. description that the wiredrawing furnace 30 of the invention has a hollow body 80, slotted at thebottom and at the ends to permit passage therethrough of the wire 12.Refractory arcuate corrugated reectors 114, secured in the side walls ofthe furnace 30, are gas heated by a plurality of burner tips 100. Thetips 100 are arranged and stacked one behind the other along thelongitudinal axis of the furnace, so that the flames therefrom sweepdown the side walls of the reflectors 114 and the corrugations 112thereon to first heat the side walls of the reflectors 114 to a whiteincandescence whereupon the gas burns along the entire peripherythereof.

The wire drawing furnace 30 of the invention permits the wire 12 to becompletely enclosed within the body 80 and the bafe 60 and containedwithin a protective atmosphere within the furnace 30. The protectiveatmosphere is created by the products of combustion which circulateabout the wire 12 within the wire heating chamber between the refractoryreflectors 114. These protective products of combustion exit at thefurnace end slots 82 and protects the wire 12 being heated within thewire drawing furnace 30 from oxidation etc. right up to the entrance ofthe wire 12 into the heated `die 140.

To facilitate the threading of the wire 12 over the guide pulley (notshown) at the entrance to the wire drawing furnace 30 and through thewire drawing die 140 at the exit end thereof, the furnace 30 is providedwith a furnace elevating mechanism 31. This mechanism 31 swings the wiredrawing furnace 30 backwards and upwards on two pivot posts 62 withoutjarring and thus avoids damaging the refractory reiiectors 114 or therefractory retaining plate 104.

The wire drawing furnace 30 of the invention uniformly heats the wire12. Minor gas pressure fluctuations within gas manifold 90 do not affectthe temperature of the wire 12. The heat baflle 60 below the wiredrawing furnace 30 retains the heat within the refractory reflectors 114thus reducing appreciably the amount of heat formerly required. Thisbaille 60 also contains the protective atmosphere created by theproducts of combustion and prevents fluctuations in the heat within thewire drawing furnace 30 due to drafts. In addition, it is impossible forthe burner tips 100 to become clogged due to aquadag falling thereon.Uniform temperature of the wire 12 which is assured by the wire drawingfurnace 30 of the invention, provides longer life for` the dies 140,appreciably reduces breakage of the wire 12 thus eliminating thenecessity for periodic Wire respooling. The furnace 30 also providessubstantial gas savings in the op# eration thereof. As a result thequality of wire 12 in the form of uniform weight of Wire is improved andproduction in the form of total length of drawn wire 12 is increased.

Although a preferred embodiment of .the invention has been disclosed itwill be understood that modifications may be made within the spirit andscope of the invention.

We claim:

1. A furnace for heating wire which is to be drawn through an adjacentdie, comprising a heat baie adapted to retain heat within the furnace,contain the products of combustion within the furnace as a protectiveatmosphere for the Wire passing therethrough and prevent fluctuations ofheat within the furnace due to drafts, a body normally partiallycontained within said heat baiiie and provided with a corrugated surfaceadapted to be disposed about said wire and adapted to slow the flow ofgas thereabout, and means associated with said body for introducing gasto said corrugated surface and heating the latter to i11- candescence tocause the gas to burn along the entire corrugated surface therebyuniformly heating the wire.

2. A furnace for heating wire which is to be drawn through an adjacentdie, comprising a heat baille adapted to retain heat within the furnace,contain the products of combustion within the furnace as a protectiveatmosphere for the wire passing therethrough and prevent fluctuations ofheat Within the furnace due to drafts, a body normally partiallycontained within said heat baille and provided with a corrugated surfaceadapted to be disposed about said wire and adapted to slow the flow ofgas thereabout, means associated with said body for i11- troducing gasto said corrugated surface and heating the latter to incandescence tocause the gas to burn along the entire corrugated surface therebyuniformly heating the wire, and means connected to said body andoperable to move said body away from said heat baffle to permit thethreading of the wire through the heat bale and into the adjacent die.

3. A furnace for heating wire which is to be drawn through an adjacentdie, comprising mounting means, a heat baffle on said mounting means andadapted to retain heat within the furnace, contain the products ofcombustion within the furnace as a protective atmosphere for the wirepassing therethrough and prevent fluctuations of heat within the furnacedue to drafts, a body normally partially contained within said heat baeand provided with a corrugated surface adapted to be disposed about saidwire and adapted to slow the ow of gas thereabout, means associated withsaid body for introducing gas to said corrugated surface and heating thelatter to incandescence to cause the gas to burn along the entirecorrugated surface thereby uniformly heating the wire, and meansconnected to said body and said mounting means and operable to move saidbody away from said heat bafe to permit the threading of the wirethrough the heat baffle and into the adjacent die.

References Cited in the le of this patent UNITED STATES PATENTS 706,031Daniels Aug. 5, 1902 1,362,367 Talley Dec. 14, 1920 1,676,176 BiggertJuly 3, 1928 1,731,055 Marchev Oct. 8, 1929 2,187,785 Hoyt Jan. 23, 19402,215,080 Hess Sept. 17, 1940 2,325,950 Green et al Aug. 3, 19432,474,313 Hess June 28, 1949 2,489,244 Stalegs Nov. 22, 1949 2,621,914Morgan Dec. 16, 1952 2,762,618 Johnson et al Sept. 11, 1956 FOREIGNPATENTS 119,334 Australia Dec. 21, 1944 883,374 France July 2, I1943386,412 Great Britain Jan. 19, 1933

